Continuous classifier for solids



July 24, 1951 R 2,561,665

CONTINUOUS CLASSIFIER FOR SOLIDS Filed Dec. 5, 1947 3 Sheets-Sheet l INVEN TOR. FEED 7. KEEN W JWM ATFOENEQJ July 24, 1951 F. 1'. KERNCONTINUOUS CLASSIFIER FOR SOLIDS 5 Sheets-Sheet 2 Filed Dec. 5, 1947INVEIJVTOR. I neza 7: zrze/v J y 24, 1951 F. T. 'KERN CONTINUOUSCLASSIFIER FOR SOLIDS 3 Sheets-Sheet 3 Filed Dec.

//O- VOLTS INVENTOR. FREE 7. lfi/E'N Patented July 24, 1951 UNITEDSTATES OFFICE CONTINUOUS CLASSIFIER FOR SOLIDS Fred T. Kern, Milwaukee,Wis. Application December 3, 1947, Serial No. 789,459

3 Claims. 1

This invention relates to improvements in devices for classifying andseparating solids, liquid in suspension, and depositing or settlingtherefrom.

" In devices of this type, the minimizing of turbulence and control ofthe flow of the suspension as to both direction and velocity, is highlyimportant and has been accomplished in the past, it at all, only byexpensive and complicated apparatus not adapted to rigid and severeoperating conditions and not suited for use with a large variety ofsolids of different size and physical characteristics.

It is an object of this invention, therefore, to provide a device toaccurately and adjustably direct and control the flow of a liquidsuspension of solids to achieve desired deposition or settling ofsolids, which device is of simple, rugged and comparatively economicalconstruction.

A further object of the invention is to pro vide a device which inaddition to controlling the flow of a liquid suspension to obtaindepositiion or settling will also automatically discharge accumulatedsolids, in such manner as to minimize disturbance of the suspension flowand to avoid discharge of any of the suspension.

" A still further object of the invention is to provide a positive andeflicient control device for the discharge of accumulated solids, whichis automatically responsive to the rise above a given maximum ordropping below a given minimum of'the accumulated solids.

' To accomplish these objects, there is provided a plurality of tanksassociated in series and increasing in the cross sectional area of flowpath f'romthe inflow tank to the outflow tank. In each tank the flow ofthe liquid suspension is directed in a downward and. upward path inorder to increase the depositing or settling of the heavier solids andcollection thereof at the bottom of each tank. Because each subsequenttank is oflarger cross sectional area of flow path, the velocity of theflow decreases thus permitting the lighter solids not settled ordeposited in previous tanks to settle or deposit in the subsequent tank.Q

An adjustable battle is placed in the upper portion of each tank andcontrols the depth of the downward path, the cross sectional area of thepath of flow and to some degree the direction of flow thus alsocontrolling the velocity of flow within each tank. The outflow from eachtank is spread by means of a launder across the larger edge of the nexttank thereby providing a quiet inflow which does not unnecessarilydisrupt the depositing or settling of solids. Thus by the use of simpleand rugged tanks with an adjustable baille the flow of liquid suspensioncan be adjusted and directed to obtain desired deposition of solids to ahigher degree of accuracy than heretofore obtained.

f Each tank is provided with a settling area and adischarge gate, thelatter being controlled by a variable volume chamber responsive to thepressure of accumulated solids within the tank. When the settling solidshave accumulated to a predetermined upper level, the gate will open anda part of the accumulated solids will be discharged until the leverthereof reaches a predetermined lower level. The gate is then closed.before the level or solids is too greatly changed to materially disturbthe flow path of the liquid suspension or permitting a material portionof thesuspension to escape.

' Objects and advantages other than those above set forth will beapparent from the above description when read in connection with theattached drawings, in which:

Fig. 1 is a top plan view of a tank arrangement' forming one feature ofthe present inven-v tion;

Fig. 3 is a section taken on the plane III-III of Fig. 1;

Fig. 4 is a perspective view of one of the tanks of Fig. 1;

Fig. 5 is a view, partially in section and partially in elevation, of agate and gate operating means for discharging material from a tank;

Fig. 6 is a bottom plan view of Fig. 5;

Fig. 7 is a partially sectional and partially elevational and somewhatdiagrammatic view of a portion of means controlling gate operation;

Fig. 8 isan enlarged view of a portion of Fig. 7; and 1 Fig. 9 is adiagram of the electric connections controlling the gate operatingmotor.

- Referring particularly to the drawings, reference numerals l5, l6 andI1 generally designate any desired number of open-topped tanks of dif-vferent sizes and connected in series. The tanks are progressively largerin total cross section area from the inflow end of the tank series attank I! to the outflow end of the series at tank 15, the tanks beingseverally wider, that is, larger in the dimension transverse to thedirection of flow of the material through the tanks, but substantiallythe same dimension in the direction of flow through the tanks, whichdimension is herein considered the length of the tanks.

The several tanks are generally similar in construction and only tank I!will be described in detail. Tank ll comprises a hopper type bottom inwhich two side walls have portions 2 I, 22 sloping toward each other toa bottom 23 and par allel portions 24, 25. The other two or end walls26, 21 are parallel and. extending in a single plane at right anglesfrom the bottom 23. One or more discharge spouts 33 extend from thebottom and severally have a gate 34 mounted thereon as will be describedhereinafter.

An inflow quieting means or distributor 38 generally in the form of anopen top box or launder extends across the'entire width of and ismounted on the tank for receiving a suspensionof solids in a liquid,from a suitable source by way of a conduit 39. The wall 40 of the inflowdistributor, toward the inside of tank, is formed with apertures 4|dividing the flow into a numberof separate streams of small volume Fig.2 is a cross section taken on the plane: II-II of Fig. 1;

and uniformly distributed over the width of the tank. The apertures maybe slots uniformly spaced in wall 40 or may be rows of circularperforations as shown. If slots are used, a stream of relatively largesize is obtained from each slot whereas rows of perforations permitfurther division of the streams so that the suspension is homogenized inpassing through the perforations and the turbulence caused by flow intothe tank is minimized.

A bafile 45 extending across the tank (see Fig. 4 particularly) ispivoted in bearings 46 on the tank walls 26, 21. By swinging on itspivots, its depth may be regulated and its angle of flow directionaltered to regulate the velocity and direction of flow through the tank.The bafile may be held in any desired position by adjustably connectingan arm 41, which is fixed on the bafile pivot, with an arm 48 pivoted ona tank wall. The lower edge 49 of the bafile is turned in the directionof flow through the tank and the baflle as a whole provides means forOhtaining a uniform flow across the entire flow area in a tank andproduces a non-turbulent rising current moving toward the outflow sideof the tank.

The tank is also provided with a box-like extension generally designated53 and receiving the suspension flow from the tank over wall 2| whichhas a flange 54 extending into the tank to form a weir allowingdischarge of only the relatively quiescent upper strata of suspensionacross substantially the entire upward flow path at the outflow end ofthe tank. From such receiver 53, the suspension discharges through rowsof perforations 55 in the receiver wall 56 and into the next tank. Itwill be understood that the suspension discharging from a tank into itsreceiver 53 has had removed therefrom a portion of the solids as will beexplained hereinafter.

Tanks l6 and 15 are generally similar to tank l1 except for provision ofa plurality of individual discharge spouts and gates for such spouts. Itis desirable to keep the weight of accumulated solids and of suspensionon any one gate below a given value. The tank [6 accordingly is providedwith three separate spouts while tank I has four separate spouts.However, the number of spouts may be varied dependent on size ofaccumulated particles and other factors. Tank [5 also has an offtakereceiver 60 for the suspension residue after passage of suspensionthrough all tanks and the bottom of receiver 60 is inclined so that allthe residue may flow into a waste conduit 6|.

Although only three tanks have been shown in the series, any number oftanks may be used depending on the number of kinds or sizes of materialto be separated from the suspension. Reference to Fig. 3 will show thatthe tanks are supported on similar frames 65, 66 and 61 and at differentlevels to cause flow of the suspension from tank to tank by gravity. Itwill be understood that the two or more spouts discharging from any tankmay be at any desired level and may discharge into the same or differentconveying means.

Each of the discharge spouts is preferably circular with an arcuate endwith which a gate 34 is associated. The gate is substantially U- shapedwith the legs of the U pivotally mounted on the spout and With the bendll of the U shaped to conform with the end of the spout and providedwith a notch 12 which is 4 substantially an isoceles triangle in shape.The gate opening is so placed that the apex of the notch moves intoregistry with the spout opening as the gate is opened. A yoke 13 ispivoted on the legs of the gate and has a rod 14 adjustably connectedtherewith to permit some lost motion of the rod relative to the yoke.

One end of rod 14 is connected with gate operating means herein shown asa reversible electric motor 11 driving a speed reducer 18 having adouble shaft with a crank disk 19 mounted on one shaft end. The gateoscillates only short distances and the degree of overrun at the end ofeach gate movement is to be minimized. One end of the speed reducershaft accordingly drives a limit switch to interrupt the motor circuitat desired times. Such switch is one of the well known types of circuitbreakers and makers and is only diagrammatically indicated at 89 in Fig.9.

The gates of any tank are preferably operated by a single drive and thegates of any tank are dependent upon the solids level in such tank andeach gate motor is controlled responsive to the pressure of the solidsbed at a given location or locations in the tank. Where a tank has aplurality of gates, a pressure responsive means is associated with eachgate and the means are so interconnected as to join in controlling themotor of such gates. The pressure responsive means may be a variablevolume chamber within the tank itself together with means fortransmitting volume variations to the outside of the tank, the wall ofthe chamber being flexibly responsive to the pressure of the accumulatedsolids bed thereon. The variable volume or flexing means actuates switchmeans in a controllin circuit for the gate operating motor. One form ofvariable volume means is shown in Figs. '7 and 8 in which a chamber witha flexible portion 86 is mounted to extend into a tank above the gate tothe minimum height at which the solids bed is to be maintained. Thechamber contains a liquid and a float 8! from which a rod 88 extendsbeyond the end of the chamber for movement of a member 89 for bridgingeither contacts 90 or 9| when the float is in the low and high positionsrespectively. The above pressure responsive means is only one example ofstructure suitable for the purpose.

In the electrical diagram shown in Fig. 9, motor 11 is provided with areversing switch 95, the form of which is dependent on the type of motorused. The motor is supplied with electrical current from a power line 96under control of a magnetically operated switch 91 and limit switch 8|]dependent upon energization of the coil 98 for operating switch 91. Atransformer 99 is connected with the power line 96 and with the member89 and contacts 90 and 9| controlling energization of the switch coil91.

In using the present structure, a suspension of solids in liquid issupplied to the inflow distributor 38 of tank I"! and is discharged intothe tank. After the tank is filled to the level of the weir 54,continued discharge into the tank creates only a slight turbulence inthe suspension for a short distance below the surface thereof. Thesuspension accordingly flows beneath the bafile 45 and over the weir 54into th outflow distributor 53 at a velocity which is substantiallyuniform as regulated, over the entire cross section area and for thefull flow length of the tank. In such flow through the relatively smallwidth of tank II, the velocity of the stream is such as to deposit orsettle solid particles of a particular kind and size. Flow through tanks[6 and in series, is similar to that above described for tank I! exceptthat the velocity is successively decreased in tanks l6 and I5, bothrelative to each other and to tank l1. Hence, the solid particlesdepositing or settling in tanks (9 and i 5 are progressively smallerthan those in tank i'l. Hence materials of one specific gravity, such asclay, may be separated from a material of a different specific gravity,such as sand, or other aggregate. One type of material such as sand mayalso be separated into three sizes.

As solids accumulate in a tank bottom, the solids bed eventually risesaround and above the flexible portion 88 of chamber 85 and presses onsuch portion to tend to collapse the same. The liquid level and thefloat 8! in the chamber are accordingly raised and raise rod 88 with itselectrically conductive member 89 to bridge contacts 9| after the solidsbed reaches a given level. The circuit of the switch coil 98 is closedand switch 91 closes the circuit of motor ll which swings the gate 10, Hclockwise to bring the apex of gate notch 12 into registry with theopening of spout 33 until the spout is completely open for dischargingsolids from the tank. Gate movement continues until motor operation isinterrupted by the limit switch 89 which may be adjusted as desired.

Discharge of the solids continues until the lowered pressure of thesolids about the flexible tube portion 86 is overbalanced by the weightof displaced liquid float 87, etc., and the flexible portion isre-expanded to its original size. This occurs before the level of theaccumulated solids de creases an appreciable amount below flexibl tubeportion. Member 89 then moves away from contacts 9| to open the circuitfor coil 98 which allows switch 91 to open. Toward the end of the motormovement, limit switch 80 is opened and reversed and reversing switch 95is operated to change the motor connections for operation in clockwisedirection. As soon as float 81 and member 89 drop sufliciently to bridgecontacts 90, coil 91 is re-energized to close switch 91 and the motorcircuit is re-closed to swin gat 10, 'H counterclockwise for closing.Gate closing continues until limit switch 89 r opens, whereupon thecircuit is placed in its original condition.

It will thus be seen that the present invention provides a tankarrangement into which suspended solids are delivered uniformly acrossthe entire width of each tank and in such manner as to minimizedisturbance of the flow in the tank. The path of flow of the suspensionthrough the tank i controlled to secure regulated and uniform flow inthe entire cross-sectional area of the flow andwithout formingnon-flowing areas or deadpockets. The discharge from the tank is uniformand is taken from across the entire area at the end of the flow path inthe tank. The lost motion in the gate drive insures gate movement andthe gate opening varies in size proportionally to the gate movement. Thegate is power operated in both directions of its movement and iscontrolled by the pressure of th accumulated solids bed to keep the bedbetween given minimum and maximum limits for respectively preventingblow by of the suspension and interference with the flow through thtank. The present structure accordingly better meets the requiredconditions for a continuous classifier than is done by any structure nowin use.

Although but one embodiment of the present invention has beenillustrated and described, it

6 will be apparent to those skilled in the art that various changes andmodifications may be made therein without departing from the spirit ofthe invention or from the scope of the appended claims.

I claim:

1. In a classifier tank for solids suspended in a liquid, a tank for theaccumulation of solids in the lower portion thereof, a discharg spout insaid lower portion, an'electric motor controlled gate associated withsaid spout for controlling the discharge therefrom, andpressure-responsive means for controlling said electric motor-operatedgate comprising a chamber having a lower flexible portion mounted insaid tank abov said spout, and a float in said chamber operativelyconnected with said electrical control means, said chamber containing aliquid on the surface of which said float is operable.

2. In a classifier tank having an electrically operated discharge gatefor controlling the dis charge of solids from said tank, the provisionof means responsive to the pressure of accumulated solids in said tankcomprising an elongated chamber extending from above the normal level ofliquid in said tank into said tank and positioned above said gate, aflexible member sealing the bottom end of said chamber, a liquid in saidchamber and said flexible member, a float movable in response to thechange of level of the liquid in said chamber, and means connecting saidfloat to the electrical control apparatus for controlling said gate.

3. In a classifier tank having an electrically operated discharge gatefor controlling the discharge of solids from said tank, the provision ofmeans responsive to the pressure of accumulated solids in said tankcomprising an elongated chamber extending from above th normal level ofliquid in said tank into said tank and positioned above said gate, aflexible member sealing the bottom end of said chamber, a liquid in saidchamber and said flexible member, a float movable in response to thechange of level of the liquid in said chamber, said chamber beingvertically adjustable to position said flexible member at th desiredminimum height at which solids collected in said tank are to bemaintained, and means connecting said float to the electrical con trolapparatus for controllin said gate.

FRED T. KERN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 701,851 Culver June 10, 1902895,092 Kirby Aug. 4, 1908 968,242 Inman Aug. 23, 1910 1,035,864Dallemagne Aug. 20, 1912 1,914,039 Parkinson et a1. June 13, 19332,150,226 Kennedy Mar. 14, 1939 2,314,421 Peterson Mar. 23, 19432,358,181 Mead et al Sept. 12, 1944 2,371,615 Haagensen Mar. 20, 19452,405,976 Patterson Aug. 20, 1946 2,408,221 Michel Sept, 24, 19462,425,551 McKay Aug. 12, 1947 FOREIGN PATENTS Number Country Date325,031 Great Britain Feb. 13, 1930

